Hydropower in Minnesota's

Future Editor's Note: Water power as a source of energy in Minnesota has many champions, and rightly so. Plans to increase the output of electricity from dams existing in our state are moving ahead.

In the following two articles, tivo Department of Natural Resources specialists — dam safety engineer Craig Regalia and aquatic biologist

§ Joseph Geis — report on two aspects of increasing our hydropower ^P resources. Regalia surveys the field and recounts what is necessary to

H® increase our energy supplies from water power. Geis describes the impact on fish and other aquatic life of one type of hydropower

j f l j l operation, then suggests ways to protect aquatic life by an alternative x^jf method.

optional energy sources are being evaluated and developed. One such 1. Cranking Up

Our Hydropower option available in Minnesota is wa t j ter power. Resource Most of the good hydroelectric Craig Regalia sites in Minnesota however, are

already occupied by dams. The good T H E HIGH COSTS and environmental news, though, is that many of these issues associated with generating dams are sitting idle. Over their electricity by fossil and nuclear fuel crests flows unharnessed energy, have caused widespread public de- Some were built to generate power bate and concern. Consequently, and did so for many years until it

High water rushes over Lake Byllesby Dam at Cannon Falls on Cannon River. Power plant, idle since 1966, is in right back-ground. Dam was completed in 1911 and operated 55 years.

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Minnesota Hydropower

became more economical to substi-tute fossil fuel or nuclear facilities. Many small hydropower plants were then either dismantled or left to de-teriorate. Using these existing dams is the most probable means of hy-droelectric expansion in Minnesota.

Some of the advantages of hy-droelectric generation are as follows:

• Dependability — down time is very low

• Nonpolluting operation • Conventional fuels are not re-

quired • Low operation and maintenance

costs • Long life of dam and generating

equipment — 50 to 100 years • Existing electric transmission

lines can be used • High plant efficiency — 85% • Dams would be maintained in

good condition, thus enhancing pub-lic safety

• Independence from commercial power suppliers.

Despite these advantages, howev-er, plans for new dams in Minnesota have progressed more slowly than expected. The primary reasons are:

• High initial costs • Necessity for engineering and

feasibility studies • Gaining the right to develop a

site • High interest rates for new con-

struction and equipment • Difficulties in arranging favor-

able power sales agreements • Difficulty developing economi-

cal operating plans compatible with

the fisheries of the watercourse in-volved. (See "Hydropower s Unex-pected Side Effect," page 59.)

Existing dams may be used by re-habilitating idle equipment, install-ing new or used equipment, or by upgrading equipment operating to-day. Although each hydro site has unique hydraulic characteristics, s tandardized tu rb ine /gene ra to r packages are available from equip-ment manufacturers.

Cost Per Kilowatt. Costs for reopening an existing small dam vary widely from site to site. A typi-cal redevelopment project using new equipment might have the fol-lowing cost breakdown:

Project design and management — 10 percent ; construction and equ ipment installat ion — 40 percent; equipment manufacture and delivery — 50 percent.

A representative total project cost would be $1,200 per kilowatt of capacity, but the cost might varv from $800/KW to $1,600/KW, de-pending on the specifics of the site and the capacity of the installation. In a recent feasibility study for the Mississippi River Dam in St. Cloud, the project cost es t imate was $9,200,000 for a 7,200 KW installa-tion. (A kilowatt is 1,000 watts.)

In Minnesota, water power pro-vides about 172 megawatts of elec-trical capacity at 28 hydro plants. (A megawatt is 1,000 kilowatts.) Minne-sota Power Company is the leader with about 109 megawatts of hvdro-

57 In Byllesby Dam power plant, water flows through large pipes — penstocks — circles turbines (center) which turn generators (left). Water continues through penstocks into river below dam. Inset: Idle control panel.

Minnesota Hydropower

power generat ing capacity at 10 generating stations. This represents about six percent of that utility's power capacity.

In the near future, MPC plans to add about six megawatts of hy-droelectric capacity and is evaluating the possibility of another 20 mega-watts for the long term. Another 20 to 50 megawatts of capacity could be added by upgrading dams owned and operated by other private com-panies. Retired sites, now owned by counties, municipalities, and the state, could add 30 megawatts.

The amount of hydroelectric ex-pansion in Minnesota will depend upon the economic feasibility of each site as determined by owner or de-veloper. Improved economic condi-tions in terms of lower interest rates could result in an additional 150 megawatts of hydroelectric capacity within 10 years. (Minnesota's elec-trical generating capacity, all forms of energy, is about 8,000 MW.)

It's unlikely, however, that addi-tional hydroelectric development in Minnesota will have a significant im-pact on the state's electrical energy needs. However, a small hydroelec-tric installation could significantly reduce energy costs for a municipal utility or private company. A one megawatt hydro station, for exam-ple, could provide most electricity for a community of 1,000 people.

Permits. In Minnesota, state law requires that a permit be obtained from the DNR for hydropower con-

struction or reconstruct ion. The primary issues addressed during the permit review process relate to dam safety and engineering feasibility, water appropriation in terms of low-flow regulation, and impacts on wildlife, fisheries, recrea t ion , navigation, flood control , water supply, and water quality.

The permit review also includes input from all levels of government, including counties, federal agencies, municipalities, watershed districts, and Soil and Water Conservation Districts.

Federal regulations require that hydroelectric projects larger than 5.0 megawatts be licensed by the Federal Energy Regulatory Com-mission. Projects smaller than 5.0 megawatts may apply for exemption from this federal licensing.

Most redevelopment projects in Minnesota will probably have a modified run-of-river mode of tur-bine operation. This type of opera-tion would primarily use the normal stream flow rather than a store-and-release peaking cycle to generate electricity. Therefore, run-of-river operations are more environmental-ly acceptable because of the smaller streamflow fluctuations caused by turbine operation. (These hydro-power operations are discussed in the article by Joseph Geis. — Ed.)

Expansion. The Minnesota State Legislature has provided funds to the DNR for cost sharing with local units of government on hydroelec-

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trie feasibility studies. Under this program the St. Anthony Falls Hy-draulic Laboratory is p repar ing feasibility analyses for clams located at St. Cloud, Granite Falls, Kettle River, Anoka, Lanesboro , Park Rapids, and Thief River Falls. These dams were selected from a hydro-power site screening study of public-ly owned dams that was prepared for the Minnesota Department of Ener-gy, Planning and Development.

The Legislature has also provided for the long term leasing of publicly owned dams for hydropower and for hydropower expansion by limiting local taxes for the first five years after development. The Minnesota Public Utilities Commission is developing

rules to encourage small power pro-duction — for dams, windmills, and solar facilities, for example — consis-tent with the protect ion of rate payers and the public.

Federal laws encourage hydro-power by requiring electric utilities to purchase power generated by small producers. Also, changes in federal tax laws provide significant advantages to hydropower develop-ers in terms of investment credits and depreciation.

Based on this generally favorable government climate and the need to develop additional sources of ener-gy, it is likely that Minnesota can look forward to hydroelectric expan-sion in coming years.

2. Hydropower's Unexpected Side Effect Joseph Geis P E O P L E V I E W hydropower as a clean source of energy — no smoke, no ash, no radiation, no environmental side effects. But fish and other aquatic life see hydropower in a different light. There is one way of opera t ing a hydro facility that threatens aquatic life. Most people are unfamiliar with this aspect of hydropower.

The driving force of hydropower is gravity. Gravity causes water to flow from a higher to a lower level. The

difference in the water elevation be-tween the pool above the dam and the water below the dam is called "head." The higher the head, the greater the waterpower.

Dams are generally classified as either low head or high head. Heads under 60 feet are generally called low head. Most dams in Minnesota being considered for hydropower are low head dams.

The most efficient turbine design for low head dams is a propeller tur-bine. The propeller looks like the prop 011 an outboard motor, except that it is larger. The propeller is in-side a tube through which water flows and is connected to a generator

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